Amplifier unit



s. LOEWE AMPLIFIER UNIT July 3, 1934.

Filed May 4, 1927 u u u w I 2" m 7. u

m f m hi CE SIEGMUND LoEwE j OR dd'aw,

BY fl/La Patented July 3, 1934 UNITED STATES PATENT OFFICE AMPLIFIERUNIT poration of Delaware Application May 4, 1927, Serial No. 188,627 InGermany July 21, 1926 2 Claims.

This invention relates to a vacuum tube amplifier and especially to anamplifier wherein the interstage coupling elements for a tube aremounted within the tube evacuated vessel with 51 the tube elements(plate, grid and filament) Heretofore, vacuum tubes have been utilizedin circuits wherein the coupling elements have been disposed externallyof the tube, necessitating complicated external wiring. According tothis inld 'vention many of the external coupling elements are placedwithin the tube thereby simplifying greatly the external amplificationcircuits, and furth r, allowing the amplifier and coupling elements tobe handled as a unit.

Consequently, it is an object of this invention to provide a vacuum tubehaving coupling elements combined therewith within a single vacuousspace. By such an arrangement, due to the decreased length of leadsrequired, it is clear that harmful electrical effects such as that duefrom stray capacities between leads will be greatly diminished.

Another object of this invention is to provide an amplifier unit whichmay readily be removed from, and replaced into, circuit.

It is a further object of this invention to provide such a unit so thatit shall have a minimum number of terminals.

Other objects and advantages of this invention will be apparent as thedescription thereof proceeds, which description will be given with theaid of the accompanying drawing, wherein:

Figure 1 shows the connection of a resistance coupled amplifier forwhich my unit is especially adapted,

Figure 2 is a side view of an embodiment of my invention and,

Figure 3 is a front view of the same.

Figure 1 shows the general diagram of connections of a four-tuberesistance-coupled radio frequency and low frequency amplifier. Thefilaments are denoted by 1, 2, 3, 4, the grids by 5, 6, '7, S; theplates by 9, 1G, 11, 12; the plate resistances by 13, 14, 15; thecoupling condensers by 16, 17,

18; the grid leaks by 19, 20, 21. The combination of such multi-stageamplifier arrangements is attended with a certain amount of circuitmounting work. It has been found convenient as pointed outbefore toevolve tubes of a kind per- 5 mitting a substantial simplification inthe work of combining such multi-stage amplifiers.

With this end in view, the circuit diagram shown in Figure 1 isseparated so that there will be the two rectangles 22 and 23 asindicated by the broken lines. Rectangle 22, as will be noted, containsa filament (2), a grid (6), a plate (10), a plate resistance (14), acoupling condenser (1'7), and a grid leak (20) as well as a number ofbinding posts adapted to permit the connection of the differentamplifier stages and establishing connection with the battery.

According to the invention, the said elements are so combinedconstructionally that the whole amplifier element can be used as a unitin proper circuit arrangements.

Figure 2 shows a side View of an embodiment of the invention, thecoupler elements (plate resistance 14, grid leak 20 and couplingcondenser 17) being built into the vacuous space in this form ofconstruction, the latter containing at the same time the amplifiersystem comprising cathode 2, grid 6 and plate 10, whereas the supplyelectrodes are all united at the base 24, preferably made of insulatingmaterial. There are two plug pins 25, 26, projected on one another inlateral view and which supply current to heat filament 2; a plug pin 27which leads to the grid 6, a pin 28 which is brought to the plate 10 byway of plate resistance 14; further, a lateral terminal 29 which isdirectly connected with the coupling condenser, and which serves forleading on to the grid 7 of the following amplifier stage 23; and ifnecessary a terminal 30 to which the end of resistance 20 is united.However, this lead-out is not absolutely necessary, since the end ofresistance 20 may be connected also with one of the ends of filament 2in the interior of the tube.

The whole structure is carried by glass rods 31 which are secured to thecompressed stem 32. 33 is the exhausted glass bulb.

Figure 3 shows another view of the arrangement. The glass bulb isindicated by 33. The amplifier system comprising plate 10, grid 6 andfilament 2 is located in the rear of the coupling elements and glasssupport 31. The connecting leads and lead-ins for the sake of clarity ofillustration have been omitted with the exception of lead-in 34 whichindicates also the seal-in points of the grid leak 20.

Amplifier units constructed as hereinbefore described, by simpleseriation and connection of the grids in the cascade permitestablishment of any desired number of amplifier stages with anegligible amount of installation work.

The coupler elements 14, 17, 20 need not necessarily be disposed insidethe vacuous space, for they may also be arranged at or in the base 24.

The arrangement of the plug pins at the base is suitably so chosen that,in the usual way, two

pins are united with the ends of the filament, one with the grid, andthe other one with the plate resistance to the plate of the built-insystem. The lead-out of the coupling condenser which is to establishconnection with the grid of the amplifier stage next above is suitablybrought to a binding post at the base of the tube.

I claim as my invention:

1. A multiple unit resistance coupled amplifier tube comprising a baseand an evacuated envelope; an anode, a control electrode and a cathodemounted concentrically with respect to each other within the evacuatedenvelope; a leak resistance, a coupling condenser and another resistancemounted in substantially one plane within the envelope; the common axisof said anode, control electrode and cathode being substantiallyparallel to the plane of said resistances and coupling condenser;contact pins on said base having connections leading to the controlelectrode, cathode and anode within said envelope; and other connectingmeans on said base having connections leading to the leak resistance andcoupling condenser within said envelope.

2. A single stage amplifier comprising in combination, a vessel, a grid,an anode and a cathode disposed within said vessel, a base aifixed tosaid vessel, a plurality of contact terminals mounted on said base, aconnection within said vessel between said anode and one of saidterminals comprising an impedance means, a connection within said vesselbetween said anode and another one of said terminals including acondenser, a connection within said vessel between the terminal side ofsaid condenser and said cathode comprising a resistance and connectionsfrom said cathode to Others of said terminals.

SIEGMUND LOEWE.

